Space lidar concept could track methane on Mars from orbit

NASA researchers have laid out a concept for measuring methane in the Martian atmosphere from space using a pulsed laser instrument operating at a wavelength of 3.3 micrometers. The proposal, published in Frontiers in Remote Sensing, describes a differential absorption lidar that would transmit alternating online and offline wavelengths targeting the strongest methane absorption line in the 3.3-micrometer band. By comparing how much light is absorbed at the two wavelengths, the instrument could determine the total amount of methane in an atmospheric column above the Martian surface.

The methane measurement alone is not sufficient to yield a concentration, because the amount of absorbed light depends on how much atmosphere the beam passes through. The concept therefore pairs the 3.3-micrometer lidar with a second instrument, a 2-micrometer lidar that measures surface pressure from orbit. Combining the column methane measurement with the surface pressure reading would allow the team to calculate the column methane mole fraction, expressed in parts per billion. Differential absorption lidar, the underlying technique, is an established remote-sensing method in which a laser tuned to an absorption feature of a target gas is compared with a nearby wavelength that the gas does not absorb.

The lower end of that range represents the detection limit, and reaching it is possible only under ideal conditions. A key caveat is technological: the concept requires the development of new fiber laser technology capable of transmitting sufficiently strong pulses at the required wavelength. The paper presents a measurement concept and its requirements rather than results from a built and flown instrument, so its performance figures are design estimates for an ideal case rather than demonstrated observations.

If the laser technology matures, the authors suggest the instrument could serve two purposes. One is scientific study of Martian weather and climate. The other is the search for potential signs of anaerobic underground life, since methane on Mars is of interest as a possible signature of anaerobic subsurface life. The authors are careful to frame this as a search capability: detecting methane from orbit would not by itself demonstrate the presence of life, and the abstract notes only that the concept could be used to look for potential signs of anaerobic underground life. The study, led by Joel F. Campbell of NASA Langley Research Center with colleagues at NASA Ames, Advalue Photonics and NASA Langley, was received in July 2026 and accepted in October 2026, and its claims are those of the authors rather than an endorsement by NASA or the publisher.

Subject of Research: A space-based 3.3 μm differential absorption lidar concept for measuring column methane mole fractions on Mars.

Article Title: Measuring methane on mars using 3.3 μm pulsed lidar from space

Article References: Campbell, J. F., Liu, Z., Lin, B., Geng, J., Yu, J., & Prasad, N. S. (2026). Measuring methane on mars using 3.3 μm pulsed lidar from space. Frontiers in Remote Sensing, 7, Article 1933329. https://doi.org/10.3389/frsen.2026.1933329

Image Credits: AI Generated

DOI: 10.3389/frsen.2026.1933329

Keywords: Mars, methane, lidar, differential absorption, remote sensing, fiber laser, atmospheric column, surface pressure, anaerobic life, Martian climate, NASA, Frontiers in Remote Sensing